The invention concerns a douche toilet including a toilet bowl having a flushing water connection for feeding flushing water, a flushing chamber defined by the toilet bowl, having a lower end and an upper end delimited by a toilet opening and which is usually closable by a toilet lid, a drain connection usually including an odor trap, normally in the form of a toilet syphon, for carrying away waste water from the flushing chamber in the course of a flushing operation, a personal cleaning device fed by way of a drinking water line for performing personal cleaning in respect of a user. Finally such a douche toilet also requires a safety device for safeguarding the drinking water network from the ingress of contaminated foul water in accordance with DIN EN 1717, which frequently is also simply referred to as “backflow protection”.
Douche toilets of that kind are frequently to be found in the Asian area and are now also increasingly widespread in Europe. Such a douche toilet virtually combines the function of a regular toilet and a bidet in one sanitary appliance or sanitary unit, thereby affording novel creative design options in the bathroom. For the purposes of personal cleaning which can thus be effected by sitting on the toilet bowl it is only necessary to operate one actuating unit so that the flushing water line which usually carries drinking water supplies water to the flushing lance.
Hitherto there are various concepts for integration of a flushing lance into a toilet or toilet bowl, but these are usually relatively complex and require attachment or installation on the toilet bowl or in the wall or the false wall behind the toilet bowl. In addition those products are relatively costly. A simple and inexpensive solution is desirable, which thus also helps that technology to make a market breakthrough in Europe, which therefore in particular involves a complex structure. The market is increasingly demanding that the bidet and the toilet bowl are matched to each other in design, which means in particular that the toilet cannot or should not be markedly longer than the bidet. As far as possible an appliance should be provided, which is integrated into a normal toilet bowl and which can be offered on the market at a good price.
For safeguarding the drinking water line which on the one hand supplies the system with flushing water for the flushing operation but on the other hand also supplies the flushing lance with drinking water, DIN EN 1717 must be taken into consideration at least for products used in Europe. That standard requires measures within a sanitary appliance, which prevent contaminated water from being drawn back into a drinking water line, for example water contaminated with feces from the flushing chamber of the toilet bowl. For that purpose DIN EN 1717 provides various measures, for example a free outlet, or a pipe interrupter. A drinking water draw-off point must generally be such that contamination of the drinking water system cannot occur. That also applies if a reduced pressure should occur in the drinking water line or if the foul water rises in the sanitary appliance (safeguard against non-drinking water being sucked or pressed back). As the toilet is connected directly to the sewerage system the strictest rules apply in that respect. Contamination of the drinking water system must always be excluded even in a damage situation. Simple mechanical backflow prevention devices or backflow flaps are therefore not reliable. System separation between drinking water and non-drinking water must always be effected by way of a free outlet. A safety distance of at least 20 mm must always be observed between that free outlet and the highest possible water level in a sanitary device. That spacing applies even when the outlet is blocked and with at the same time water flowing thereto or in the event of waste water being pushed back out of the foul water line. The highest possible water level in a toilet is in that case the toilet opening which is normally closeable by a toilet lid with toilet seat. To sum up therefore DIN EN 1717 requires technical measures for preventing foul water from being sucked back into the drinking water line in the event of a pressure drop, which is summarized by the key word of “back-suction safeguard”.
That problem of back-suction safeguard was already addressed in one of the first patent applications in this area of technology, more specifically in DE 1129896 dating from the year 1957, in which the safeguard was achieved in a complicated fashion by a free outlet into a container and a downstream-connected pump for again building up a pressure. Another solution without a pump with an injector is proposed in CH 444076 dating from the year 1965. In that solution leakage water which can always occur with that kind of safety device is passed into the flushing chamber over the top edge of the toilet pan.
In other countries different technologies are used for resolving the problems outlined in the opening part of this specification, in which respect DIN EN 1717 does not have to be taken into account in Asia. In the United States “vacuum breakers” are preferably employed, which are frequently integrated in an attachment device on the top side of the pan, constituting “technical unit in the lid”. The relatively high mounting locations of the toilet lid, which are linked to those solutions, involve toilets of a longer design configuration, which is not always desirable.
In existing douche toilets the height of the toilet opening defines the overflow edge for the foul water in a damage situation, that is to say therefore the highest possible level of foul water in the toilet bowl. As in accordance with DIN EN 1717 a minimum spacing 2 cm between that highest possible level of foul water in a damage situation and a water outlet opening fed by drinking water is required existing safety devices are always arranged at least 2 cm above the toilet opening. That is effected either in a—relatively ugly—cistern or structure between the toilet and the wall or false wall behind the toilet or in the false wall behind the toilet, as described for example in German patent application DE 100 05 254. The mounting complication and expenditure on site is however considerable with such a solution.
Taking that state of the art as its basic starting point, the object of the invention is to at least partially avoid those disadvantages and in particular to provide a compact douche toilet which fulfills the requirements of DIN EN 1717.